I think next month is the anniversary of GalCiv, and Brad had said pretty much that a new game announcement is coming soon.
Also, the reasons SD went Steamworks are resource-related, so I don't expect that to change. (They said, doing FE Steamworks and non-Steamworks cost them a good bit of time, and Steam was the majority of sales, despite Stardock building up their base non-Steam for a decade)
Realistically, given the above- it's very reasonable to assume a GalCiv 3 announce within the next month, and that it will require Steamworks. I suspect you'll see more Steamworks integration from Stardock in GalCiv3 than you did with LH- and hopefully it allows for MP.
That's not a guarantee in any way though- I can be wrong, or Brad might change the order up just to make me wrong. ^_^